Prevention of discoloration of cloth



Patented Dec. 29, 1970 3,551,338 PREVENTION OF DISCOLORATION F CLOTH Anthony A. Rapisarda, Elmhurst, N.Y., assignor to Lever Brothers Company, New York, N.Y., a corporation of Maine No Drawing. Filed Sept. 15, 1967, Ser. No. 668,163 Int. CL Clld 7/56 US. Cl. 252-99 8 Claims ABSTRACT OF THE DISCLOSURE The specification discloses a stain inhibitor system which prevents or diminishes staining which occurs when textiles are laundered in a solution; containing manganese ions and a bleaching agent which is capable of oxidizing the manganese.

The inhibitor system comprises a water-soluble titanium compound and an inorganic condensed polyphosphate. This inhibitor system can be incorporated into a detergent formulation, a bleach formulation, or it can be added to the bath separately before the bleach is added.

This invention is directed to the laundering of textiles and, more particularly, to the preventing of the discoloration of textile surfaces during laundering and bleaching.

Bleaching is an important aspect of textile laundering, and detergent compositions which contain bleaching agents are widely used. Bleaches are incorporated into a detergent formulation or are added separately to the laundering solutions. The bleaching action may be achieved during the washing cycle or by a separate exposure of the textiles to the bleaching agent after the detergent has been rinsed out. It has been observed that textile surfaces are often discolored when contacted with bleaching agents in the presence of manganese ions. Since the water supplies of many communities contain significant quantities of manganese ion, it isf-apparent that a serious problem exists for both home and commercial laundries. Investigation has shown that the formation of yellow or brown stains on textiles during bleaching is the result of the deposition of a manganese compound, probably manganese dioxide, on the cloth surface. The term bleaching is intended to include both'exposure to a bleaching agent in a bleaching path per se or in a combined bleachdetergent bath. Bleaching agents, which release chlorine or oxygen, oxidize the manganese ions in the solution to form a manganese compound which is then deposited on the surface of the cloth. As little as 0.1 part per million of manganese ion in the water will cause objectionable stains on cloth withinto washes when the textile is exposed to the manganese ion and a bleaching agent which can oxidize the manganese. As little as 1 to 3 parts per million of manganese ion in the wash water along with about parts per million of oxygen or about 200 parts per million of chlorine will severely discolor the cloth in a single wash.

The need for protection against discoloration is particularly required within the pH range generally encountered in the laundering of textiles,'that is, at a pH between about 5 and about 10.5. It is within this range that manganesecompound stains are found to deposit on the cloth and tenaciously adhere thereto.

It is an object of this invention to prevent the discoloration of the textile surfaces when laundered in a solution which contains manganese ions.

Another object of the invention is to provide a discoloration inhibiting composition for use in manganesecontaining water.

It is a further object to provide detergent formulations which can be used safely in conjunction with the bleaching of textiles despite the presence of normally objectionable amounts of manganese ion in the bleach solution. Another object of the invention is to provide non-staining bleach-containing solutions.

These and other related objects are accomplished by the use of a discoloration inhibitor composition when textiles are treated with or exposed to a solution containing manganese ions and a bleaching agent which is capable of oxidizing the manganese ions. Discoloration of the textiles caused by oxidation of the manganese ions can be prevented by the presence, in the solution, of an elfective amount of an inhibitor composition comprising a watersoluble titanium compound and an inorganic condensed polyphosphate. The term effective amount as used herein refers to an amount of the inhibitor composition which is capable of preventing the formation ofmanganese stains normally encountered when textiles are exposed to an aqueous solution containing manganese ions and a bleaching agent which is capable of oxidizing manganese ions, i.e., a stain-inhibiting amount. Accordingly, the term effective amount can be used to describe the concentration of inhibitor components in solution which will prevent or diminish staining. Similarly, the' term effective amount" can be used to describe the amount of inhibitor components in a detergent or bleach formulation which, upon dissolution, will provide a concentration of inhibitor in solution which is suflicient to prevent staining. The actual amount of the inhibitor composition which is necessary to adequately protect against discoloration and provide optimum results depends on a number of conditions, for example, the expected degree of staining and discoloration, .which, in turn, depends upon the concentration of manganese ion in the water supply and the amount and the nature of the bleaching agent which is present in the water. The solubility of the titanium compound must be considered also. 3

The term water-soluble, as used herein with respect to the titanium compounds, is intended to describe those compounds haying a sulficient degree of solubility to provide the low concentration levels of titanium ions in the wash or bleach water which are necessary for the prevention or diminution of staining, as hereinafter disclosed. Suitable water-soluble titanium compounds include titanium dichloride, titanium trichloride, titanium fluoride, titanium nitrate, titanium oxalate, and the like.

The condensed inorganic polyphosphates suitable for use in the inhibitor composition are well-known materials commonly employed in detergent formulations. These compounds are frequently employed as builders in detergent formulations, since the presence of such materials normally enhances the detergency of the active organic detergent material. Suitable condensed inorganic polyphosphates, which can be employed in combination with the above-described titanium compounds, include the alkali metal tripolyphosphates and pyrophosphates, e.g., sodium tripolyphosphate, sodium pyrophosphate, potassium pyrophosphate, and the like.

The inhibitor compositions comprising a water-soluble titanium compound and an inorganic condensed polyphosphate have been found to be etfective in preventing the discoloration of textile surfaces which occurs when the textiles are washed or bleached in solutions which contain manganese ions and a bleaching agent capable of oxidizing the manganese ions. Representative manganese-oxidizing bleaching agents include potassium persulfate, ammonium persulfate, sodium hypochlorite, calcium hypochlorite, sodium perborate, alkali metal dichloroisocyanurates, alkali metal trichloroisocyanurates, lauroyl peroxide, sodium peroxide, ammonium dipersulfate, hydrogen peroxide, and any other bleaching agents which are capable of oxidizing manganese ions to a higher valence state.

The discoloration inhibitor compositions, described above, can be formulated conveniently into detergent formulations or bleach formulations for concurrent addition to the washing or bleaching solution in amounts which are sufiicient to provide an effective amount of the inhibitor composition when added to the wash or bleach solution. For example, the inhibitor can be ad mixed conveniently with liquid or powder synthetic detergent formulations which contain one or more anionic or nonionic detergents in combination with various inorganic builders, fillers, perfumes, germicides, brighteners, solvents, dispersing agents, soil suspending agents, and any other ingredients commonly employed in detergent formulations. Alternatively, the inhibitor compositions can be packaged separately in either liquid or dry form for selective addition to a washing or bleaching solution. The inhibitor composition can be provided in solid form in combination with a filler, builder or bulky agent for selective addition to the wash or bleach solution. Such fillers include sodium sulfate, sodium metasilicate, trisodium phosphate, disodium hydrogen phosphate, borax, sodium perborate, sodium chloride, trisodium nitrilotriacetate, ethylenediamine tetraacetic acid, and the like. The diluent need not contain a polyphosphate since the required polyphosphate can be supplied by using a polyphosphate-containing bleach or detergent formulation. For example, the inhibitor, detergent and bleach can be added separately from different containers, provided that theinhibitor, i.e., the titanium-polyphosphate composition is added before substantial reaction between the bleach and the manganese has occurred. Accordingly, the inhibitor composition can be added before the bleach, simultaneously with the bleach, or very shortly after the bleach.

It will be appreciated that the diluent need not be inert in the washing or laundry bath, but can perform some function such as corrosion control, disinfecting action, pH control or the like. However, since such diluents, are inert with respect to strain prevention they are herein referred to as inert diluents. The water soluble titanium compound can be packaged with an inert diluent for use as a pre-bleach additive in conjunction with phosphate-containing bleaching or detergent formulations.

Whatever method of formulation is selected, the inhibitor composition should be added to the solution either before or at substantially the same time as the bleach. More precisely, the inhibitor must be present when the bleaching agent contacts the manganese ions, since the herein disclosed inhibitors will not remove stains once they are formed.

Generally, it has been found that the presence of from about 0.1 to about 50 parts per million of titanium ion and from about 50 to about 3,000 parts per million of a condensed inorganic polyphosphate in the wash or bleach solution is capable of providing adequate stain inhibition. It is preferred to employ from about 0.5 to about parts per million of titanium ion and from about 100 to about 1,000 parts per million of the polyphosphate, based on the wash or bleach solution.

The selection of an organic detergent for use in conjunction with the stain inhibiting compositions of this invention is not narrowly critical. The detergent may be any water soluble anionic or nonionic compound having detergent properties. A detergent acts by altering the interfacial effects at the various phase boundaries within the system, and the terms detergency and detergent" are used to refer to the cleaning of solid objects by means of a liquid vbathin such a way that the cleaning process primarily involves a physico-chemical action other than solution, though solubility factors may be involved, for

example, in preventing or diminishing redeposition of soil and dirt removed from the surface.

Examples of suitable anionic detergents which fall within the scope of the term detergent include the soaps, i.e., water-soluble salts of higher fatty acids, or rosin acids,

such as may be derived from fats, oils, and waxes of animal, vegetable, or marine origin. Preferred soaps include the alkali metal salts, particularly sodium and potassium salts of tallow, grease, coconut oil, tall oil, and mixtures of such oils. Other detergents include synthetic anionic detergents, such as the sulfated and sulfonated synthetic detergents, particularly those having from about 8 to 26, and preferably from about 12 to 22, carbon atoms in the hydrophobic portion of the molecule. Particularly preferred are the sulfated and sulfonated synthetic detergents derived from saturated higher fatty acids having from about 8 to about 26 carbon atoms. Examples of suitable saturated higher fatty acids are myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, and lignoceric acid.

As examples of suitable anionic detergents there may be mentioned the higher alkyl mononuclear aromatic sulfonates, such as higher alkyl benezene sulfonates containing from about 10 to about 16 carbon atoms in alkyl group, e.g., sodium salts of tetrapropyl, hexyl, octyl, nonyl, decyl, dodecyl, and keryl benzene sulfonates. Higher alkyl toluene, xylene, and phenol sulfonates may be used also, as well as the higher alkyl naphthalene sulfonates, such as sodium di-isopropyl naphthalene sulfonate, ammonium diamyl naphthalene sulfonate, and sodium dinonyl naphthalene sulfonate.

Another group of anionic detergents includes sulfated aliphatic alcohols, such as sodium dodecyl sulfate, sodium hexadecyl sulfate, triethanolamine dodecyl sulfate and sodium oleyl sulfate, sulfated and sulfonated fatty oils, acids, and esters, such as the sodium salts of sulfonated castor oil and sulfated red oil; sulfated hydroxyamides such as sulfated hydroxy-ethyl lauramide; the sodium salt of lauryl sulfoacetate; sodium salt of dioctyl sulfosuccinate; and the sodium salt of oleyl methyl tauride can also be used in conjunction with the stain inhibitor compositions of the instant invention.

Additional anionic detergents which can be employed include the sulfuric acid esters of polyhydric alcohols ,esterified with higher fatty acids, e.g., coconut oil monoglyceride monosulfate, tallow diglyceride monosulfate; and the hydroxy sulfonated higher fatty esters, such as the higher fatty acid esters of low molecular weight alkylol sulfonic acids, e.g., oleic acid ester of isethionic acid.

The stain inhibitors herein disclosed can be used in conjunction with nonionic surface active agents, i.e., compounds in which the small highly ionized group characteristic of ionic type surface active agents has been replaced by a long chain containing a series of weakly hydrophillie groups, such as ether linkages or hydroxyl groups. Such nonionic surface active agents are well known in the art, and particularly include such agents as the condensation productsof alkyl phenols with alkylene oxides, e.g., the reaction product of iso-octylphenol with from about 6 to about ethylene oxide units; the condensation products of higher fatty alcohols, such as tridecyl alcohol, with alkyl'ene oxides; the condensation products of fatty oils, such as tall oil with alkylene oxides; alkylene oxide adducts of rrf onoesters of hexahydric alcohols and ethers thereof, e.g., sorbitan monolaurate, sorbitol monooleate, and mannitan monopalmitate. Other nonionics include the condensation products of polypropylene glycols with alkylene oxides and the higher fatty acid alkylolamides, such as diethanolamide of coconut oil fatty acids, and the like.

Other suitable nonionic detergents include the surface active derivatives of polyglycerols.

These anionic and nonionic detergents are merely illustrative. Many other suitable detergents and surface active agents are known to those in the art and they are described in the literature, e.g., in Surface Active Agents, by Schwartz and Perry, Interscience Publishers, New York, 1949.

The following examples describe atest laundry procedure employed to facilitate the evaluation of the ability of the herein disclosed stain inhibitors to prevent manganese discoloration.

In this procedure, swatches of white cloth were washed in a wash-water containing about 0.1 part per million of manganese ions, 180 parts per million, calculated as calcium carbonate, of calcium and magnesium ions in a molar ratioof about 2: 1, about 0.25 weight per cent of a detergent formulation, as described, and about 200 parts per million of chlorine. The cloths were washed, under conditions which simulated normal laundry procedure, in a small washing machine with the temperature of the wash solution at about 120- F. The wash procedure consisted of awash cycle and a fresh water rinse cycle. After rinsing, the cloths were squeeze-dried. The cloths were washed a total of ten times using each of the described detergent formulations. Refiectance measurements were made on each sample after the second, fifth, and tenth wash, using a General Electric Recording Spectrophotometer at a setting of 430 millimicrons. The reflectance for each measurement on the various formulations are given in the following examples.

EXAMPLE 1 The following spray-dried nonionic detergent composi- 1 Dodecylphenol condensed with moles (avg) of ethylene oxide.

2 Polyoxypropylene having a molecular weight of from 1,500 to 1,800. The washing procedure outlined above was followed. The reflectance measurements on these samples are given below:

Composition number It can be seen from the above data that the detergent formulation containing titanium trichloride, i.e., Composition 2, is characterized by a significantly higher refiectance than the control. This increased reflectance indieates' the substantial reduction of manganese staining on the cloths washed with the inhibitor-containing formulation.

EXAMPLE 2 The influence of a bleaching agent on cloth washed in a manganese-containing solution is illustrated by the following tests. Pieces of cotton cloth were washed in a wash watercontaining 90 parts per million of hardness, calculated as calcium carbonate, and 0.1 part per million of manganese ion using about 0.25 weight percent of the detergent formulations shown in Example 1, above. The washing was conducted in two series. In one series about 200 parts per million of chlorine were added to the wash solution. In the second series no bleaching agent was used. The complete laundry cycle consisted of a fifteen minute wash period at about 120 F., followed by a three minute rinse. The laundry cycle was repeated ten times and reflectance measurements were made after the second, fifth, and tenth wash by a General Electric Recording Spectrophotometer set at 430 millimicrons. The results are tabulated below:

Composition (1) Composition (2) Wash Number:

This example illustrates the ability of titanium ions (Composition, 2) to prevent or diminish the discoloration of textile surfaces caused by the simultaneous presence of manganese ion and a bleaching agent as compared to a control composition containing no titanium compound (Composition 1).

EXAMPLE 3 Four solutions, as shown below, were prepared from water containing 3 parts per million of manganese ion and 200 parts per million of chlorine supplied in the form of sodium hypochlorite:

(l) 1000 ppm. sodium tripolyphosphate;

(2) 1000 ppm. sodium tripolyphosphate and 30 p.p.m.

titanium tri'chloride;

(3) 1000 ppm. tetrasodium pyrophosphate;

(4) 1000 p.p.m. tetrasodium pyrophosphate and 30 p.p.m. titanium trichloride.

Solution number Cloth Type:

This example shows that the discoloration occurs when manganese ions and bleach are present even in the absence of organic detergents and that titanium ions significantly improve stain inhibition whether or not organic detergents are present.

Table I below sets forth results obtained in a series of tests in which swatches of white cloth were immersed in a series of solutions (A through L) which contained both manganese ions and a bleaching agent capable of oxidizing the manganese ions. In addition to the ingredients shown in Table I, all the solutions contained 3 parts per million of manganese ion and parts per million of hardness, calculated as calcium carbonate (calcium/magnesium ratio of 2:1).

The Wash procedure consisted of a wash cycle and a fresh water rinse cycle after which the cloths were squeezed dry. Reflectance measurements were made on each sample using a General Electric Recording spectrophotometer at a setting of 430 millimicrons. The reflectance for each measurement on the various samples is shown in the table.

Comparison of the reflectance measurements shown in columns A and B shows that in the absence of a polyphosphate titanium does not inhibit staining.

Comparison of the results shown in columns B, C, and B shows that a mixture of titanium ions and sodium tripolyphosphate is superior to either titanium alone or sodium tripolyphosphate alone as a manganese stain in- TABLE I 4. The method of claim 3 wherein a stain inhibiting amount is at least about 0.1 part per million of titanium ion and at least about 50 parts per million of said poly phosphate.

5. A composition for use as a pre-bleach additive to laundry solutions consisting essentially of manganese ions, a bleaching agent capable of oxidizing manganese ions, and a condensed inorganic polyphosphate, said composi- P.p.m. in washing solution Formula A B G D E F G H I .l' K L Mn++ 3 3 Pure TPP 1 1, 000 Cl (from Clorox) 200 C1 (from K-DOA 200 NHiAlfol 14126.1

E0-S04 250 TiOl: 42. 5 42. 5 TSPP 1,000 1,000 TKP Cloth N o. 1 reflectano 89. 7 90. 9 88.5 89. 1 90. 7 91. 0 Cloth No. 2 reflectanc 90. 4 90. 8 88. 5 87. 7 91. 2 87. 4 88. 9 67. 3 91. 1 92. 0

Average 75. 8 60. O 90. 0 90. 9 88. 5 88. 4 90. 9 88. 0 88. 7 (i7. 3 90. 9 91. 5

1 Contained an estimated 1% pyrophosphate. 2 Potassium dichlorocyanurate.

3 Ammonium salt of a. suliated condensate of an average of 3.1 moles of ethylene oxide per mole of a mixture of aliphatic alcohols of 12 and 14 carbon atom chain length.

Those skilled in the art will appreciate that various modifications and changes may be made in the compositions of this invention and in the manner of using such compositions, without departing from the spirit of the invention. Accordingly, it will be understood that the scope of the invention is to be limited only by the appended claims.

I claim:

1. A method for inhibiting the formation of manganese stains on textiles contacted with a solution consisting essentially of manganese ions and a bleaching agent capable of oxidizing the manganese ions, said method comprising the prevention of stain development by incorporating in said solution a stain inhibiting amount of an inhibitor composition consisting essentially of a Water-soluble titanium compound and a condensed inorganic polyphosphate, said composition being added to the solution before substantial reaction between the bleaching agent and the manganese has taken place.

2. The method of claim 1 wherein a stain inhibiting amount is at least about 0.1 part per million of titanium ion and at least about 50 parts per million of said inorganic polyphosphate.

3. A method for bleaching textiles in a solution consisting essentially of manganese ions and a 'bleaching agent capable of oxidizing the manganese ions, said method comprising incorporating in the solution a stain inhibiting amount of a composition consisting essentially of a watersoluble titanium compound and a condensed inorganic polyphosphate.

tion consisting essentially of a diluent inert with respect to stain prevention and a stain inhibiting amount of a water-soluble titanium compound.

6. A manganese stain inhibiting composition consisting essentially of stain inhibiting amounts of a condensed inorganic polyphosphate and a water-soluble titanium compound, said composition being capable of inhibiting manganese staining of textiles in solutions consisting essentially of manganese ions and a bleaching agent capable of oxidizing the manganese ions.

7. A non-staining bleaching composition for use in manganese-containing solutions which consists essentially of a bleaching agent capable of oxidizing manganese, and a stain inhibiting amount of the stain inhibitor composition of claim 1.

8. A detergent formulation consisting essentially of a water-soluble organic detergent and a stain inhibiting amount of the stain inhibitor composition of claim 1.

References Cited UNITED STATES PATENTS MAYER WEINBLATT, Primary Examiner.

U.S. Cl. X.R. 8108, 111 

